Necessary duration of follow-up to assess complications of mesh in hernia surgery: a time-lapse study based on 460 explants.

PURPOSE: Risk of complications following hernia repair is the key parameter to assess risk/benefit ratio of a technique. As mesh devices are permanent, their risks are life-long. Too many reports in the past assessed mesh safety prematurely after short follow-ups. We aimed to explore what length of follow up would reveal the full extent of complications. METHODS: Time lapses between implantation and excision were analyzed in 460 cases of meshes excised for complications after hernia repair. Patterns of percentage growth and time lapses at 50th and 95th percentiles were used to compare groups of different hernia type, age, gender and reason for excision. RESULTS: The 50th and 95th case percentiles in the dataset were at 3.75 and 15.0 years between mesh implantation and excision. For hernia types, the longest time lapses were for groin hernias (4.0 and 16.11 years at 50th and 95th percentiles). The shortest were for umbilical hernias (2.16 and 9.68 years). Males had later excisions than females (4.11 and 16.1 vs. 2.47 and 9.79 years). Younger patients (< 45 y.o.) had later excisions than older patients (4.12 and 17.68 vs. 3.37 and 10.0 years). Out of all subgroups, the longest time lapses were for groin hernias in younger males (4.77 and 18.89 years) and for mesh erosion into organs (4.67 and 17.0 years). CONCLUSIONS: Follow-up of more than 15 years is needed to fully assess complications after mesh hernia repair. Especially longer periods are needed to detect mesh erosion into organs and complications in younger males. Presently, short observations and lack of reporting standard in the literature prohibit accurate assessment of complication risks. We propose to use cumulative incidence for standardized risk reporting (y% risk at x years). This will show time-dependent patterns and allow comparisons between different techniques and studies of variable duration. Standardization will also help to predict long-term risks beyond shorter (practical) follow-ups and facilitate real-time monitoring during surveillance.

Correction to: Pure tissue repairs: a timely and critical revival.

In the original publication, author group, abstract text, position of Figure 1, Figure 5 legend, Figure 6 (duplication of figure panels) and the conflict of interest statement were incorrectly published. The corrected text and the figures are given here.

Pure tissue repairs: a timely and critical revival.

"The majority of hernias can be satisfactorily repaired by using the tissues at hand. The use of mesh prosthesis should be restricted to those few hernias in which tension or lack of good fascial structures prevents a secure primary repair. This group includes large direct inguinal hernias and incisional hernias in which the defect is too large to close primarily without undue tension. Most recurrent hernias, because of this factor are best repaired with mesh prosthesis". These words, penned in 1960 by Francis Usher have reconfirmed what had been a mantra of the Shouldice Hospital (Usher in 81:847-854, 1960). The Shouldice Hospital has specialized in the treatment of abdominal wall hernias since 1945. It has, since its beginning, insisted on the fact that a thorough knowledge of anatomy coupled with large volumes of surgical cases would lead to unparalleled expertise. It was Cicero who taught us that "Practice, not intelligence or dexterity, will win the day"! Since the seminal contribution of Bassini (1844-1924), there have been no less than 80 procedures imitating his inguinal herniorrhaphy and much more since the introduction of mesh and mesh devices (Iason in Hernia. The Blakiston Company, Philadelphia, pp 475-604, 1940). All have failed to some extent and it appears that the common denominator for these failures was the inability to understand the importance of entering the preperitoneal space. Only Shouldice and McVay (Lotheissen, Narath) realized the shortcoming and have continued to thrive as a successful procedure. Entering the preperitoneal space eliminates any temptation to plicate the posterior inguinal wall, a layer normally deficient in direct inguinal hernias, but it also allows the identification of muscle layers rectus, transversus and internal oblique muscles which will go to reconstruct the posterior inguinal wall, without tension as reported by Schumpelick (Junge in 7(1):17-20, 2003).

A mechanism of mesh-related post-herniorrhaphy neuralgia.

PURPOSE: The objective is to compare nerve densities in explanted polypropylene meshes in patients with or without chronic pain. Pain has supplanted recurrences as a complication of hernia surgery. The increased incidence of pain mirrors a parallel increase in the use of polypropylene meshes. Neither triple neurectomy nor careful nerve preservation has brought relief. Perhaps because we have forgotten that nerves, in response to some evolutionary mechanism, tend to regenerate, undergo changes imposed by prosthetic elements and architecture, mimicking entrapment and compartment syndromes. METHODS: A total of 33 hernia meshes have been analyzed: 17 excised due to severe pain, two for combined pain and recurrence, 14 sampled during revision for recurrence without pain. Each mesh had standardized sampling for histology and the nerves were highlighted by S100 stain. Nerve densities were assessed within the mesh spaces and in tissue outside the mesh. RESULTS: The density of nerves present in the standardized mesh samples of patients complaining of pain was much more elevated than in the mesh of those patients who had a recurrence but no pain. The difference was statistically significant (p < 0.001). Excluding two patients who had both pain and recurrence, the difference was even more marked (p < 0.0001). CONCLUSIONS: Re-innervation and neo-innervation are known to take place following hernia repairs in indigenous tissue as well as through polypropylene meshes. However, when pain is an overriding issue dictating mesh explant, the degree of mesh innervation is significantly higher when compared to mesh excised for recurrence. That increase has been confirmed statistically.

Structural alterations of prosthetic meshes in humans.

The use of prosthetic mesh in abdominal wall hernia surgery is a well-accepted practice. What is not settled, however, is the type of prosthesis that best suits the purpose. The narrow choice today means a prosthesis of polyester or polypropylene. These are available in many designs, configuration of weave, thickness of weave and strand, and size of pore. There has been a pervasive feeling that these materials "shrink". To what extent they do has not been accurately defined. This study was designed to measure such "shrinkage". Interestingly, our measurements revealed that prosthetic meshes could "expand" as well as "shrink". The extent to which they do varies between -40% and 58.5%. Whereas it was felt that fibrocyte activity and its eventual scar formation accounted for the "shrinkage" of the mesh, we have discovered that structural alterations in the size of the mesh pores can be affected by distilled water, saline, blood, formalin, bleach, as well as in vivo implantation. Prosthetic meshes are, therefore, not the inert materials they are claimed to be and can expand as well as shrink. We have, unfortunately, not been able to correlate the degree or direction of change to any known parameter.

Transversalis fascia rediscovered.

The transversalis fascia is a layer in the make-up of the posterior inguinal wall. It is the deepest, thinnest, and least important layer in terms of the prevention of herniation. It is a segment of the wider endoabdominal fascia. The true posterior wall of the inguinal canal is formed, in varying degrees, by the muscles or aponeuroses of the internal oblique and transversus abdominis. Plainly, Daedalus was not needed to show surgeons and anatomists how to make a labyrinth out of a rabbit hole!

Complications of groin hernia surgery.

Groin hernias represent one of the most common procedures performed in general hospitals. The rapid changes that have been witnessed in prosthetic materials, open-approach surgeries, and laparoscopic techniques have made hernia surgery a most interesting field of endeavor that demands renewed discipline and dedication.

The Shouldice technique: a canon in hernia repair.

Controversy exists on the merits of the various approaches to inguinal repair. Evolution of the classic open repair has culminated in the Shouldice repair. Challenges from newcomers, namely, tension-free repair and laparoscopy, are being examined. These two techniques have a number of disadvantages: the presence of foreign bodies (prostheses) and their implication in cases of infection; the cost of prosthetic material, which is no longer negligible (particularly with expanded polytetrafluoroethylene); and problems of safety in that the laparoscopic approach is no longer a dependable asset except in the hands of a highly specialized and dextrous operator. Still, complications occur with laparoscopic repair that should not be associated with a surgical procedure that is considered benign, safe and cost-effective. Surgeons must recognize the pertinent facts and decide according to their conscience which method of repair to use.

[Shouldice herniotomy]. / Die Herniotomie nach Shouldice.

The Shouldice operation has evolved to become the classic procedure for open pure tissue repair for inguinal hernias. The operation is an important part of a surgeon's repertoire as he may need to perform the procedure at some critical time, especially when faced with strangulation, when tension-free prosthetic repairs and laparoscopic approaches fail. When properly done, the Shouldice repair yields results that have set standards for all other techniques to emulate. Other particular advantages of the technique are: safety, the use of local anaesthesia, benign postoperative complications and the cost, which is the most reasonable of all surgical techniques.

The rational use of mesh in hernias. A perspective.

The decision to use mesh in abdominal wall hernia repairs is not always based on rationale. Some surgeons use mesh on nearly all cases, encouraged by the impression that they never get recurrences. Other surgeons rarely use mesh, citing the fact that there is always enough tissue on site and that foreign bodies can have their complications. A third group of surgeons will respond to the particular need of that herniorrhaphy. Because few surgeons have a large personal experience, it becomes difficult to scan the spectrum of hernias seen in the surgical population. Yet, when numbers are available, a pattern may be discerned which reveals four classes of hernias. These four classes are those which require mesh--"rarely" (less than 1%), "sometimes" (less than 5%), "frequently" (38% and 63.3%) and "always" (91.0% and 100%). These statistics should provide surgeons with some insight as to when mesh may be used.

The space of Bogros and the deep inguinal venous circulation.

The ideal reconstruction of the floor of the inguinal canal during a herniorrhaphy implies a good anatomic dissection and exposure. This cannot be accomplished without entering the subinguinal space of Bogros. This space presents a venous circulation that has not been entirely identified in the past. As an aid to accomplishing a safe and bloodless dissection, these vessels have been described--the deep inferior epigastric vein, the iliopubic vein, the rectusial vein, the retropubic vein and the communicating rectusio-epigastric vein, and their relationship into a venous circle. The need to map these vessels is becoming more crucial as surgeons choose varied approaches to the space of Bogros and insert synthetic mesh that requires anchoring.